There are many categories of hazards that might be encountered in a laboratory setting, and situations can change frequently. Even after you have identified and controlled all current risks, it is critical that you remain open to the possibility that new unexpected dangers can arise. Periodically verify the hazards are required. All employees who work with hazardous chemicals must be apprised of the hazards of chemicals present in their work area. This training must be provided before initial assignment and before new exposure situations. Personal protective equipment necessary for the safe handling of hazardous substances must also be provided. Employees who work with chemicals in laboratories must be trained on the Laboratory Standard. Additional training is required when new exposure situations arise. Such situations include the use of new chemicals, greater quantities of chemicals, and different procedures.